German Foreign Minister Frank-Walter Steinmeier and Iraqi Kurdish President Masud Barzani have agreed that Turkey must continue with the peace process despite the increase in violence, a German Foreign Ministry spokeswoman has said.

Steinmeier and Barzani spoke by phone on July 28 and "agreed that the PKK and Turkey must resume the peace process, and that an escalation only serves the extremists," according to the spokeswoman.

Also, on July 29, Turkey's parliament held a special session at the request of the opposition to discuss the air strikes against the Islamic State (IS) militants and the Kurdish Workers Party (PKK) rebels as well as Erdogan's call for parliament to strip politicians with links to the militants of immunity from prosecution.

Turkish jets launched their heaviest assault on Kurdish militants in northern Iraq overnight since the air strikes began last week, a senior official told Reuters.